1. Field of the Invention
The present invention relates to a vehicle including a body frame that leans and two front wheels which are arranged side by side in a left-right direction of the body frame.
2. Description of the Related Art
A vehicle is known which includes a body frame that leans in a left-right direction of the vehicle when the vehicle turns to the left or the right and two front wheels which are arranged side by side in a left-right direction of the body frame (refer to Japanese Patent Publication No. 2011-057018A, for example). This type of vehicle is able to turn with its body frame leaning from a vertical direction. More specifically, the body frame leans rightward in the left-right direction of the vehicle when the vehicle turns to the right, while the body frame leans leftward in the left-right direction of the vehicle when the vehicle turns to the left. As this occurs, the relative positions of the left front wheel and the right front wheel in an up-down direction of the body frame changes.
The vehicle described in Japanese Patent Publication No. 2011-057018A uses a configuration that is a so-called leading arm mechanism in order to permit a change in the relative position of the left front wheel and the right front wheel to the body frame when the vehicle takes a turn. This configuration includes a left upper arm, a left lower arm, a right upper arm, and a right lower arm that extend in a front-rear direction of the body frame. The configuration also includes a left knuckle arm and a right knuckle arm that extend in the up-down direction of the body frame. The left front wheel is supported by the left knuckle arm. The right front wheel is supported by the right knuckle arm. Respective rear portions of the left upper arm and the right upper arm are supported on a front portion of the body frame. Respective front portions of the left upper arm and the left lower arm are supported on the left knuckle arm. The left upper arm and the left lower arm are able to turn relative to the body frame about a pivot shaft that extends in the left-right direction of the body frame. This allows the left front wheel that is supported on the left knuckle arm to be displaced in the up-down direction of the body frame. Respective rear portions of the right upper arm and the right lower arm are supported on the front portion of the body frame. Respective front portions of the right upper arm and the right lower arm are supported on the right knuckle arm. The right upper arm and the right lower arm are able to turn relative to the body frame about a pivot shaft that extends in the left-right direction of the body frame. This allows the right front wheel that is supported on the right knuckle arm to be displaced in the up-down direction of the body frame.
The vehicle described in Japanese Patent Publication No. 2011-057018A includes a balance beam that extends in the left-right direction of the body frame. The balance beam is supported on the body frame. The balance beam is able to turn about a shaft that extends in the front-rear direction of the body frame. The left lower arm is connected to a left end of the balance beam via a left shock absorber. The right lower arm is connected to a right end of the balance beam via a right shock absorber. This allows the displacement of the left front wheel in the up-down direction to be associated with the displacement of the right front wheel in the up-down direction. For example, when the left front wheel is displaced upwards in the up-down direction of the body frame, a left end of the balance beam is displaced upwards in the up-down direction of the body frame, while a right end of the balance beam is displaced downwards in the up-down direction of the body frame. This displaces the right front wheel downwards in the up-down direction of the body frame.
In addition, the vehicle described in Japanese Patent Publication No. 2011-057018A is a so-called sport-type vehicle. In the vehicle described in Japanese Patent Publication No. 2011-057018A, the power drive is disposed between the front wheels and the rear wheel in the front-rear direction of the body frame. In the vehicle described in Japanese Patent Publication No. 2011-057018A, the fuel tank is disposed directly above the power drive in the up-down direction of the body frame. In the vehicle described in Japanese Patent Publication No. 2011-057018A, the seat is disposed directly behind the fuel tank in the front-rear direction of the body frame. The vehicle described in Japanese Patent Publication No. 2011-057018A is a vehicle on which the rider rides in such a way as to straddle the body frame. Namely, a portion of the body frame which is disposed ahead of the seat on which the rider sits when he or she rides the vehicle in the front-rear direction of the body frame is disposed between both feet of the rider.
The leading arm mechanism includes the upper arm and the lower arm that extend in the front-rear direction of the body frame for each of the left front wheel and the right front wheel. The upper arm and the lower arm pivot individually about the pivot shaft that extends in the left-right direction of the body frame. Therefore, the movable ranges of the left front wheel and the right front wheel in relation to the up-down direction of the body frame is easily increased. In the event of the displacement amount of the relative position of the left front wheel and the right front wheel in the up-down direction of the body frame being great, the angular range in which the body frame is able to lean in the left-right direction of the vehicle is increased. Consequently, the leading arm mechanism is suitable for a sport-type vehicle for which a large leaning angle of the body frame in the left-right direction of the body frame is desired.
In order to increase the angle at which the body frame is able to lean in the left-right direction of the vehicle, it is necessary to increase the variation in the relative position of the right front wheel and the left front wheel in the up-down direction of the body frame. Accordingly, it is necessary to increase the dimensions of the upper arms and the lower arms that define the leading arm mechanism in relation to the front-rear direction of the body frame. In other words, it is necessary to increase the distance between the pivot centers of each upper arm and each lower arm and each front wheel in relation to the front-rear direction of the body frame. As this occurs, the overall dimension of the vehicle in the front-rear direction of the body frame is increased. Further, each upper arm and each lower arm that are large in size in the front-rear direction move greatly in the up-down direction of the body frame about the pivot shaft. Therefore, it is inevitable that the movable range of the leading arm mechanism is increased. Since it is necessary that the individual constituent components that are mounted at the front portion of the vehicle are disposed so as to avoid the movable range of the leading arm mechanism, the front portion of the vehicle tends to be enlarged in size.